Progressive Protrusive Tongue Exercise Does Not Alter Aging Effects in Retrusive Tongue Muscles

Purpose: Exercise-based treatment approaches for dysphagia may improve swallow function in part by inducing adaptive changes to muscles involved in swallowing and deglutition. We have previously shown that both aging and progressive resistance tongue exercise, in a rat model, can induce biological changes in the genioglossus (GG); a muscle that elevates and protrudes the tongue. However, the impacts of progressive resistance tongue exercise on the retrusive muscles (styloglossus, SG; hyoglossus, HG) of the tongue are unknown. The purpose of this study was to examine the impact of a progressive resistance tongue exercise regimen on the retrusive tongue musculature in the context of aging. Given that aging alters retrusive tongue muscles to more slowly contracting fiber types, we hypothesized that these biological changes may be mitigated by tongue exercise.Methods: Hyoglossus (HG) and styloglossus (SG) muscles of male Fischer 344/Brown Norway rats were assayed in age groups of young (9 months old, n = 24), middle-aged (24 months old, n = 23), and old (32 months old, n = 26), after receiving an 8-week period of either progressive resistance protrusive tongue exercise, or sham exercise conditions. Following exercise, HG and SG tongue muscle contractile properties were assessed in vivo. HG and SG muscles were then isolated and assayed to determine myosin heavy chain isoform (MyHC) composition.Results: Both retrusive tongue muscle contractile properties and MyHC profiles of the HG and SG muscles were significantly impacted by age, but were not significantly impacted by tongue exercise. Old rats had significantly longer retrusive tongue contraction times and longer decay times than young rats. Additionally, HG and SG muscles showed significant MyHC profile changes with age, in that old groups had slower MyHC profiles as compared to young groups. However, the exercise condition did not induce significant effects in any of the biological outcome measures.Conclusion: In a rat model of protrusive tongue exercise, aging induced significant changes in retrusive tongue muscles, and these age-induced changes were unaffected by the tongue exercise regimen. Collectively, results are compatible with the interpretation that protrusive tongue exercise does not induce changes to retrusive tongue muscle function.

P155 Effects of upper airway muscle training on upper airway physiology in people with obstructive sleep apnea

Introduction Previous studies demonstrate that oropharyngeal exercises can reduce obstructive sleep apnoea (OSA) severity. However, the physiological mechanisms underlying this improvement are unknown. Thus, this study aimed to evaluate the effects of a speech-pathology led, targeted upper airway muscle training protocol on upper airway physiology. Methods People with mild-moderate OSA (n=12 studied to date, 5 females, 7 males) completed 12 weeks of daily upper airway muscle training targeting the muscles of the tongue and soft palate. Pre- and post-training outcome measures included anterior and posterior tongue muscle strength and endurance and upper airway collapsibility via the upper airway collapsibility index. Results Preliminary findings indicate that 12 weeks of targeted exercise training improved anterior and posterior tongue muscle strength, respectively (54.3±12.7 vs. 61.5±7.7kPa, p<0.01, 50.1±8.5 vs. 58.0±8.5kPa, p<0.01), and anterior and posterior tongue muscle endurance, respectively (15.7±10.9 vs. 24.1±8s, p<0.01, 9.5±4.2 vs. 23.3±17.7s, p<0.01). The upper airway collapsibility index improved post-training (25.5±18.9 vs. 12.26±12.11 %, p=0.03). Conclusions Twelve weeks of upper airway muscle training improved tongue muscle strength, endurance and upper airway collapsibility in people with mild-moderate OSA. These physiological changes provide insight into the potential mechanisms mediating reductions in OSA severity with oropharyngeal exercises. This research was supported by the 2019 Phillips/ASA Sleep Research grant.

Tongue stretching: technique and clinical proposal

Objectives The tongue is an organ with multiple functions, from sucking to phonation, from swallowing to postural control and equilibrium. An incorrect position or mechanics of the tongue can causes sucking problems in the newborn or atypical swallowing in the adult, with repercussions on the position of the head and neck, up to influencing upright posture and other problems. Tongue dysfunctions are quite frequent (10–15%) in the population. For the manual therapist, this frequency indicates one to two subjects every 30 patients. Exercises have been proposed to improve the tone and strength of the swallowing muscles but the results are not so clear in the literature. The aim of this study is to describe and provide a tongue muscle normalization technique that helps the manual therapist in the treatment of problems related to it. Methods The literature has been investigated through pubmed, Google scholar of the last 10 years, the keywords used and combined with the Boolean operators AND and OR, are: “tongue, tongue habits, tongue diseases, taste disorder, neck pain, posture, postural balance, atypical swallowing, muscle stretching exercise, tissue expansion, soft tissue therapy, osteopathic manipulative treatment”. Results and Conclusions The technique is possible to be executed even in a sitting position, in the case the patient is unable to assume a supine position, the subject should provides immediate feedback that allows the therapist to understand if the technique has been correctly executed. The simplicity of execution and application of the technique makes it a possible and immediate therapeutic tool in the clinical setting.

Muscle volume and intramuscular fat of the tongue evaluated with MRI predict malnutrition in people living with dementia: a five-year follow-up study

Malnutrition is highly prevalent in older persons with dementia. Therefore, strong predictors of malnutrition in this population are crucial to initiating early interventions. This study evaluates the association between the probability of having malnutrition with the muscle volume and intramuscular fat (iMAT) of the masseter and the tongue in magnetic resonance images (MRI) of community-dwelling older persons diagnosed with mild dementia followed for five years. This is a longitudinal study conducted in the western part of Norway. Muscle volume and iMAT of the tongue and masseter were computed from structural head MRIs obtained from 65 participants of The Dementia Study of Western Norway (DemVest) using Slice-O-Matic software for segmentation. Malnutrition was assessed using the glim index. Linear mix models were conducted. Having malnutrition at baseline was associated with lower muscle volume (OR 0.60 SE 0.20 p=0.010) and higher iMAT (OR 3.31 SE 0.46 p=0.010) in the tongue. At five years follow-up, those with lower muscle volume (OR 0.55, SE 0.20 p=0.002) and higher iMAT (OR 2.52, SE 0.40 p=0.022) in the tongue had a higher probability of presenting malnutrition. The masseter iMAT and volume were not associated with malnutrition in any of the adjusted models.In people diagnosed with mild dementia, tongue muscle volume and iMAT were associated with baseline malnutrition and the probability of developing malnutrition in a 5-year trajectory. In the masseter, there were no significant associations after adjustments.

The Effect of DREADD Activation of Leptin Receptor Positive Neurons in the Nucleus of the Solitary Tract on Sleep Disordered Breathing

Obstructive sleep apnea (OSA) is recurrent obstruction of the upper airway due to the loss of upper airway muscle tone during sleep. OSA is highly prevalent, especially in obesity. There is no pharmacotherapy for OSA. Previous studies have demonstrated the role of leptin, an adipose-tissue-produced hormone, as a potent respiratory stimulant. Leptin signaling via a long functional isoform of leptin receptor, LEPRb, in the nucleus of the solitary tract (NTS), has been implicated in control of breathing. We hypothesized that leptin acts on LEPRb positive neurons in the NTS to increase ventilation and maintain upper airway patency during sleep in obese mice. We expressed designer receptors exclusively activated by designer drugs (DREADD) selectively in the LEPRb positive neurons of the NTS of Leprb-Cre-GFP mice with diet-induced obesity (DIO) and examined the effect of DREADD ligand, J60, on tongue muscle activity and breathing during sleep. J60 was a potent activator of LEPRb positive NTS neurons, but did not stimulate breathing or upper airway muscles during NREM and REM sleep. We conclude that, in DIO mice, the stimulating effects of leptin on breathing during sleep are independent of LEPRb signaling in the NTS.

Reliability of Sonoelastography Measurement of Tongue Muscles and Its Application on Obstructive Sleep Apnea

Few studies have explored the feasibility of shear-wave ultrasound elastography (SWUE) for evaluating the upper airways of patients with obstructive sleep apnea (OSA). This study aimed to establish a reliable SWUE protocol for evaluating tongue muscle elasticity and its feasibility and utility in differentiating patients with OSA. Inter-rater and intra-rater reliability of SWUE measurements were tested using the intraclass correlation coefficients. Submental ultrasound was used to measure tongue thickness and stiffness. Association between the ultrasound measurements and presence of OSA was analyzed using multivariate logistic regression. One-way analysis of variance was used to examine if the values of the ultrasound parameters varied among patients with different severities of OSA. Overall, 37 healthy subjects and 32 patients with OSA were recruited. The intraclass correlation coefficients of intra‐ and inter-rater reliability for SWUE for tongue stiffness ranged from 0.84 to 0.90. After adjusting for age, sex, neck circumference, and body mass index, the risk for OSA was positively associated with tongue thickness [odds ratio 1.16 (95% confidence interval 1.01–1.32)] and negatively associated with coronal imaging of tongue muscle stiffness [odds ratio 0.72 (95% confidence interval 0.54–0.95)]. There were no significant differences in tongue stiffness among OSA patients with varying disease severity. SWUE provided a reliable evaluation of tongue muscle stiffness, which appeared to be softer in patients with OSA. Future longitudinal studies are necessary to investigate the relationship between tongue softening and OSA, as well as response to treatment.

Gene delivery to the hypoglossal motor system: preclinical studies and translational potential

Dysfunction and/or reduced activity in the tongue muscles contributes to conditions such as dysphagia, dysarthria, and sleep disordered breathing. Current treatments are often inadequate, and the tongue is a readily accessible target for therapeutic gene delivery. In this regard, gene therapy specifically targeting the tongue motor system offers two general strategies for treating lingual disorders. First, correcting tongue myofiber and/or hypoglossal (XII) motoneuron pathology in genetic neuromuscular disorders may be readily achieved by intralingual delivery of viral vectors. The retrograde movement of viral vectors such as adeno-associated virus (AAV) enables targeted distribution to XII motoneurons via intralingual viral delivery. Second, conditions with impaired or reduced tongue muscle activation can potentially be treated using viral-driven chemo- or optogenetic approaches to activate or inhibit XII motoneurons and/or tongue myofibers. Further considerations that are highly relevant to lingual gene therapy include (1) the diversity of the motoneurons which control the tongue, (2) the patterns of XII nerve branching, and (3) the complexity of tongue muscle anatomy and biomechanics. Preclinical studies show considerable promise for lingual directed gene therapy in neuromuscular disease, but the potential of such approaches is largely untapped.

AGE DYNAMIC OF THE MOTOR EVOKED POTENTIAL FROM THE TONGUE IN HEALTHY PERSONS

Целью нашей работы было определение параметров вызванного моторного ответа (ВМО)с мышц языка у здоровых лиц разного возраста при транскраниальной магнитной стимуляции (ТМС). Обследованы 62 здоровых человека 2-75 лет (34 женщины и 28 мужчин), не имеющих неврологических заболеваний и нарушений речи. Всем проводили диагностическую ТМС по одноимпульсному протоколу наложением кольцевого койла на голову в проекции точки Fz по схеме «10-20» для стимуляции прецентральной извилины и поверхностного отводящего электрода с постоянным межэлектродным расстоянием на язык по центральной линии. У всех испытуемых был зарегистрирован ВМО с мышц языка. Средняя латентность ответа составила 7,14±0,63 мс, амплитуда - 1,79±1,09 мВ. Достоверных отличий при сравнении показателей латентности и амплитуды ВМО в зависимости от гендерного фактора получено не было. Между детьми 2-17 лет и более старшими здоровыми лицами (18-55 и 56-75 лет) регистрировали достоверные отличия по показателям амплитуды и латентности ВМО с языка. В трёх возрастных группах показатели латентности составляли 6,21±0,45; 7,05±0,76; 7,27±0,64 мс соответственно, амплитуды - 0,81±0,61; 1,88±1,01; 1,69±0,92 мВ соответственно. Достоверные отличия по показателям амплитуды и латентности ВМО с языка могут отражать происходящие с возрастом изменения - удлинение кортико-лингвальных путей вследствие развития нервной системы, а также увеличение объёма языка и последующие инволюционные изменения нервной и мышечной ткани. Our aim was to determine parameters of motor evoked potential (MEP), elicited by the transcranial magnetic stimulation (TMS) from the tongue in healthy persons of different age. 62 neurologically healthy individuals without any speech problems (age range from 2 years old to 75 years, 34 females & 28 males) were enrolled. All underwent diagnostic TMS, single-pulse protocol, 90-sm round coil, Neiro-MS-D device. Coil was placed on Fz point, registration was performed by the surface electrode on the middle line of the tongue. Results. MEPs were of different appearance, but were registered in all cases, its average latency was 7,14±0,63 ms, average amplitude - 1,79±1,09 mV. There were no gender differences. Significant age difference ( p <0,001) was registered between children (age 2-17 years) and two older groups (18-55 and 56-75 years) both on latency and on amplitude. MEPs latency was in three age groups, respectively, 6,21±0,45; 7,05±0,76, and 7,27±0,64 ms. MEPs amplitudes were 0,81±0,61; 1,88±1,01 and 1,69±0,92 mV, respectively. In healthy people aged 2-75 years MEP from the tongue may be registered in 100 % of the cases; its average latency is 7,14±0,63 ms, average amplitude - 1,79±1,09 mV; there are no significant gender differences, but significant age differences. TMS of the tongue according to this protocol is relatively simple, not time-and efforts-consuming & may be widely implemented in clinical neurophysiology. There are significant differences on MEPs latencies and amplitudes in healthy persons, which may reflect age-related changes - lengthening of the cortico-lingual pathways and tongue muscle maturing in the childhood and then fibrous tissue development and other changes in nervous tissue and tongue muscle, developing with age.